Consider the grid environment below. The robot is initially located at $A,B,$ or C with equal probabilities, and the robot's goal is to reach the destination T and stay there. In each time step, the robot may stay put or move from its current grid cell to a neighboring cell deterministically. If the robot tries to move to a neighboring cell occupied by obstacles, it stays unmoved in its current cell. There are no observations.

$($a$)(3$ Points$)$ Of the three probabilistic models that we have discussed in the class, MDP$,$ HMM, and POMDP, which one is most suitable for this task and why?

$($b$)(4$ Points$)$ Describe a policy for the robot to reach T with probability $1.$